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March 2023

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12 discussions

data families/newtype instances allow `DatatypeContext`s ?
by Anthony Clayden 13 Mar '23

13 Mar '23

https://discourse.haskell.org/t/choosing-data-representation-based-on-type/… A `DatatypeContext` on a `newtype instance` gets the usual warning it's deprecated. But the decl is accepted -- at GHC 8.10. (It doesn't achieve what the O.P. was asking for -- but then I wouldn't expect it to.) Is this behaviour deliberate, or more of an accident? I'm surprised such a modern feature (datatype families) tolerates such an old/deprecated feature. I suppose this means the two features are orthogonal -- which is kinda a Good Thing (wrt some continuing discussions). AntC

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[ANNOUNCE] GHC 9.6.1-rc1 is now available
by Ben Gamari 03 Mar '23

03 Mar '23

The GHC team is very pleased to announce the availability of the first (and likely final) release candidate of GHC 9.6.1. As usual, binaries and source distributions are available at [downloads.haskell.org](https://downloads.haskell.org/ghc/9.6.1-rc1/). Beginning with GHC 9.6.1, GHC can be built as a cross-compiler to WebAssembly and JavaScript. This is an important step towards robust support for compiling Haskell to the Web, but there are a few caveats to be aware of in the 9.6 series: - Both the Javascript and WebAssembly backends are still at an early stage of development and are present in this release as a technology preview - Using GHC as a cross-compiler is not as easy as we would like it to be; in particular, there are challenges related to Template Haskell - GHC is not yet run-time retargetable; a given GHC binary targets exactly one platform, and both WebAssembly and JavaScript are considered platforms for this purpose. Cross-compilers must be built from source by their users We hope to lift all of these limitations in future releases. Additionally, 9.6.1 will include: - Significant latency improvements in the non-moving garbage collector - Efficient runtime support for delimited continuations - Improvements in compiler error messages - Numerous improvements in the compiler's memory usage See the [release notes][] for a comprehensive accounting of changes in this release. As always, one can find a migration guide to aid in transitioning from older releases on the [GHC Wiki][migration-guide]. We have also recently started extending our release process to cover a wider set of Linux distributions. In particular, we now offer Rocky 8 and Ubuntu 20.04 binary distributions which cover RedHat-derivative and distributions using older `glibc` releases (namely 2.27), respectively. Please do give this release a try and open a [ticket][] if you see anything amiss. If all goes well we expect the final release should be available by late next week. Happy Haskelling, ~ Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/issues/ [migration-guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.6 [release notes]: https://downloads.haskell.org/ghc/9.6.1-rc1/docs/users_guide/9.6.1-notes.ht…

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